Western Power Distribution Case Study

WPD is the electricity distribution company for South West England, Midlands and South and West Wales. WPD deliver electricity to 7.8 million customers over a 55,300 sq km service area. The company operates one major Control Centre in Cardiff which has responsibility for all 132kV, 33kV and 11kV networks operated throughout the company’s area.

PDH Network

In June 2006 Cherry & White were invited to tender for a pilot network implementation which would provide more resilience and security to the existing fibre optic network and a vehicle for integration of potentially some 103 hill top base stations. The geographical spread for the networks covers the South West of England and South Wales. The tender was successfully won in July 2006 and design, implementation, training and commissioning were achieved by the end of September 2006. Following the successful implementation, the second phase of contract was awarded in June 2007 with the added objective of interconnection of a new £5 million IP-PMR system consisting of some 2000 handsets. This system provides for voice, mobile ENMAC and rural automation data The centralised management based upon a CXR SNMPc workstation is implemented via a separate CISCO Ethernet network Final commissioning was achieved at the end of September 2007 – a repeat of the previous year which facilitated the new IP- PMR system going live for November 2007. Architecture The core of the system is based upon the Cherry & White QX3440 TDM PDH High Density Multiplexer which provides DACS(Digital Access Cross Connect System) with full DSO cross connect of backplane capacity up to 128Mbs.

Implemented above this with the new extension is the Cherry & White MX Multiservice Access platform providing connectivity to the E3 radio network . Local networks are supported in redundant ring structures utilising the QX3440 at E1 levels and interconnecting to E1 radios and the MX muxes are utilised to integrate the separate E3 radio networks. These systems replace the previous Nortel networks.

Following on from the above network we were approach by Western Power Distribution to provide a replacement for the aging Nortel SDH network which was being made end of life, they also required full training, network design, installation and commissioning services along with a 5 year 24/7 service and maintenance contract.

SDH Network

They required approximately 50 x HX9416RA STM16 nodes configured into multiple SNCP rings that would merge together at 4 central sites, they also had the need for 13 STM4 nodes that would make up many smaller sub rings & spurs that would hang off the main STM16 Cherry & White network. The network needed to be integrated into an existing 10G optical DWDM system, therefore channelised optics needed to be used.

The Synchronization of the network was achieved by using an external GPS timing unit connected at one of the sites where the STM16 rings merge, there is also a backup timing unit at one of the other merging sites in case the primary source fails. SSM was used to indicate the clock quality around the network.

This network was designed to be the core transport network for an existing 500 node PDH network. The network needed to be resilient and well protect so all nodes had dual CPU’s and PSU, The network was also configured in an SNCP ring topology to ensure that the failure of a node did not affect traffic around the network.